This section provides background information related to the present disclosure which is not necessarily prior art.
Many personal and commercial vehicles have been constructed with an internal combustion engine for transferring power to the driven wheels of the vehicle. Older vehicles may be equipped with exhaust systems that may not meet present governmental regulatory standards or standards that are about to be imposed. When new, these vehicles may have met the emissions control regulations but these vehicles may require modification to be legally operated in the future.
In one example, commercial vehicles such as buses may be equipped with a diesel fueled internal combustion engine having an exhaust system that does not include a diesel particulate filter or a regeneration unit associated with the diesel particulate filter. In addition, many of these same vehicles have relatively simple engine and driveline arrangements where an electronic engine controller is not provided.
It may be desirable to retrofit certain vehicles with exhaust systems including a diesel particulate filter and a regeneration unit. Some emissions control systems require a real time indication of engine operating speed to properly manage the regeneration unit. Furthermore, operation of the regeneration unit may require a secondary supply of oxygen that may be provided by an external air pump. Accordingly, it may be desirable to provide an exhaust system including a diesel particulate filter, a regeneration unit, a secondary air supply including an air pump where the air pump is equipped with a sensor operable to output a signal indicative of the internal combustion engine speed.